One can double the vertices appearing in the diagrams in a symbolic way, following [1]}, as:
\(V_{Qh} & = &Q_1h_1-Q_2h_2 = Q_+h_-+Q_-h_+ \\V_{Qh^2} & = &Q_1 h_1^2 - Q_2 h_2^2 = 2Q_+h_+h_- +Q_- h_+^2+\frac{1}{4}Q_-h_-^2 \\V_{h^3} & = &h_1^3-h_2^3 = \frac{1}{4}h_-^3+3h_-h_+^2\) 
